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How Ornithopters Fly

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Articulated flapping wings

Description of flapping wing constructions
which have been developed together with the EV-models

1. Requirements of the flapping wing

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2. Aeroelastic controlled articulated
flapping wing

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3. With adjustable twisting moment

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4. With increasing wing twisting near the wing tip

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5. Aeroelastic controlled articulated flapping wing
with adjustable twisting moment and expanding wing twisting near the wing tip

downstroke twisting upstroke twisting
downstroke twisting upstroke twisting

Maximum intended wing twisting (click on picture)

In flight practice the articulated flapping wing has a big advantage. The bending of the hand wing in comparison to the arm wing depends on lift of the hand wing. At the same time it determines the distribution of the angle of incidence along the wing span. If the amplitude of the bending is estimable on flight pictures, the lift forces of the hand wing in comparison to the gliding flight can be estimated. Furthermore, the distribution of the angle of incidence in the moment of the picture was taken can easily be suggested (please look at EV6 and EV7). With these tow information's selective adjustments of the twisting moment of the flapping wing, the driving power and the cycle time ratio are possible. Especially flight pictures taken approximately in the middle of up- and downstroke are informative.

Note

In this paper you can find some more details about the
Articulated flapping wings (in German, PDF 1.3MB).

Informations and suggestions for a further development you will also find in the article Lift during wing upstroke (PDF 0.7 MB).

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6. Covering of flapping wings

Here the description of the manufacturing processes of the

Covering of a flapping wing with an elastic film

(in German, PDF 360 KB)